I agree, at the level of detail you are talking about, price quotes for an intended special order bass, a telephone call might be a good idea.
One other thought about Ebony lams. I don't know, I'm just guessing, but I'm thinking that part of the cost of an Ebony lam upgrade is for the extra labor involved. I belive it has been posted here before that Ebony is just more difficult to work with than other woods. Thus even if you could supply your own Ebony for neck lams, I'm guessing there would still be additional labor involved in working with the wood and thus a consequent additional cost as well.